Recovery of oil and meal from oil-bearing marine life



W. C. DAVIS Oct. 14, 1952 RECOVERY 0F oIL AND MEAL FROM OIL-BEARINGMARINE LIFE 5 Sheets-Sheet 2 Filed June 6, 1947 BYU M ATTORNEY W. C.DAVIS Oct. 14, 1952 RECOVERY OF OIL AND MEAL FROM OIL-BEARING MARINELIFE Filed June 6, 1947 5 Sheets-Sheet 1 /NVENTOR #4u 75H C Al//s BY/ ama W. C. DAVIS Oct. 14, 1952 RECOVERY OF' OIL AND MEAL FROM OIL-BEARINGMARINE LIFE Filed June 5, 1947 5 Sheets-Sheet 5 4. /NVENTOR VAL 715/?//z//s A TTOPNEY W. C. DAVIS Oct. 14, 1952 RECOVERY OF OIL AND MEAL FROMOIL-BEARING MARINE LIFE 5 Sheets-Sheet 4 Filed June 6, 1947 A TTORNE YOct. 14, 1952 w. c. DAvls y 2,514,110

RECOVERY OF OIL AND MEAL FROM OIL-BEARING MARINE LIFE Filed June 6, 19475 Sheets-Sheet 5 /N VE N TOR ML TER C. Q4 ws ATTORNEY -are separatedfrom Patented Oct. 14, 1952 RECOVERY or oIL AND MEAL FROM ont-BEARINGMARINE LIFE Walter C. Count-Y,

Davis, Tredyffrin Township, Chester Pa., assignor to The Shar-plesCorporation, a corporation of Delaware Application .lune 6, 1947, SerialNo. 752,916 l Claims. (Cl. 260--412.1)

This invention pertains generally to the processing of fish for therecovery of solids and oil therefrom, and pertains more particularly tothe processing of whole fish and/or portions thereof, such as wholeportions, for the above purposes.

In the conventional treatment of fish for the recovery of fish oil andfor the production of a solid product which may be used, for example, asfertilizer or as animal or fowl feed, the raw fish parts, which maycomprise all of the fish, the heads, tails, or other offal, orotherwise, are usually cooked with live steam. The cooked fish parts arethen passed to a screw press for the recovery of meal and oil.

The meal discharged from the screw press may be used, after drying, forexample, as fertilizer, or as animal or fowl feed.

The liquor from the screw press contains water, solids and oil. A largepart of thesolid matter is initially separated from this liquor such asby gravity settling, after which the liquor may be passed to a highspeed centrifugal machine in which iish oil may be' separated from waterand residual solids.

Normally this conventional treatment is carried on in a series of stepsrequiring, besides screw 'press facilities, large holding tanks for usein the various steps of the process. This bulky equipment is costly toinstall andloccupies considerable space. Furthermore, th'e'sc'rew pressin this type of application requires frequent adjustment, resulting inshut-downs for this purpose, and consequent loss of timev which at timesmay be very considerable. Moreover, in this conventional process asizable pro-portion of oil usually remains in the meal unless thisresidual oil is 'extracted from the meal such as by solvent extractionwhich is relatively expensive. High oil content meal is not considereddesirable for use as cattle or fowl feed.

The present invention requires no bulky equipment, and yields asubstantially larger proportion of separated oil than can be obtained-bythe use of a screw press. The process preferably is'carried on in aclosed system and may be completely continuous.

In practicing the present invention, raw whole sh and/or portionsthereof, :such as whole portions, heads, tails, livers, or other oal,etc. are cooked, and thereafter treated, preferably con` tinuously, forthe separationof solids from liquids. This separation may beaccomplished by continuously feeding the cooked mass into a centrifugalmachine in the operation of which solids liquid, and thereafter subwise,solids and/ or liquids A'zones of the bowl.

feed quality from fish solids.`

jected to centrifugal force while disposed in a thin layer such as whilebeing impelled to a Zone closer to the axis of rotation than the `zoneof discharge of liquidl and unseparated solids. The separated solids arethus wrung relatively dry of liquids and thereafter discharged fromrthemachine relatively free from liquids. vThereafter the liquid andunseparated solids vare treated, such as continuously, to separate waterand oil from each other and from previously Luiseparated or residualsolids.v may be accomplishedfby feeding theliquid and unseparated solidsinto a second centrifugal machine in the operation of whichsclidsaredischarged from a zone adjacent to the inside.. pe-

riphery of the bowl, while liquids, such as water and iish oil, areseparately discharged fro-mother If desired, such as for the furtherrecovery of oil, and/or the recovery of 'meal having a higher proteincontent,y or otherdischarged from either centrifugal machine, or both,and 4separately or in admixture, may be furthertreated, such as byrecycling, or otherwise. For example, separated water containing proteinand separated solids from the second separation step of the process, maybe added to separatedsolids fromthefirst separation step, and theresulting mixture processed to recover meal content. The term iish isemployed herein in its broad sense and will be understood to .includeall oil-bearing marine life,.portions thereof and other offal asdescribed above. Y, 1

Thus a feature of thepresent invention resides inthe recoveryof fishoilin'high yieldsf;V 1,

A further feature of thel invention resides in the recovery of mealhaving a relatively low `oil content and/or having a relatively highprotein content.

a simplek and continuous process `for the recovery of oil andsolidslfromfish in which compactland l continuously operating machineryY. is. employed. Another feature of this invention .residesintherecovery of a relatively high yield Vof mealnof Further features 1 andadvantages tion will becomerapparentto :those skilledinthe art uponbecoming familiar withl the following detalled description andthevattached drawings,

inwhich, f Figure l is a :flow` sheet i11ustratingcne Vbodiment of theii'ivention,

Figure 2 is arrowsheetfiiiustratirieanother embodiment of the invention,

The latter separation having, a `higher. protein ofthe inver.

Figure 3 is a view with parts cut away and parts in section of one ofthe centrifugal machines which may be employed in the invention,

Figure 4 is a View with parts cut away and parts in section of anothertype of centrifugal machine which may be employed in the process of theinvention, and

Figures 5a and 5b together comprise a now sheet illustrating anotheradaptation o1" Athe invention to a continuously operating closed system.

In the process diagrammatically illustrated in Figure 1, nsh, which maybe whole sh, portions of sh or any combination thereof, are fed into acooker I0. This cooker which conveniently is of a continuous type may beheated with live steam or by any other suitable means. The fish areusually held in this cooker for a suflicient length of time and at asufficiently high temperature to more or less completely cook the fleshyparts and to disintegrate the fish substantially. Conveniently, water,such as ordilnary water, or stick-water to be hereinafter moreparticularly defined, or otherwise, may be added to the fish in thecooker to speed the cooking process and to aid in disintegration of thefish. The addition of water to the cooker is not a necessity, as in manyinstances ish themselves contain sufficient water for cooking, and inothers the condensate from steam may add enough water, or conditions maybe otherwise such 'as to make the addition of water to the cooker .notessential. When water is added, stick-water which contains large amountsof soluble protein, and which is one of the products of the process, maybe used. Since stick-water,

which is normally discarded, contains considerable heat, heat will bethus saved in cooking, and as hereinafter more particularly set forth,meal of higher protein content may be recoveredY The cooked fish fromthe cooker I are passed, such as by means of pump II, into a centrifugalmachine I2 for the separation of solids from liquids. This machine maybe of the general type illustrated in Figure 3 and described indetailhereinafter. In the operation of this machine, solids areseparated from liquids and then centrifuged while disposed in a thinlayer to separate further liquid therefrom. In an embodiment of amachine of this type, solids are impelled to and discharged from a zonecloser to the axis of rotation than the zone of discharge of liquids andunseparated solids.

As illustrated, separated solids are conveyed from machine I2 throughconduit I3, and liq- `uids containing unseparated solids through conduitI4.

Liquids comprising water and oil, and unseparated. solids fromcentrifugal machine I2 are passed,.such as by pump I5 in conduit I4, toa second centrifugal machine I6. Machine I6 may be of the typeillustrated in Figure 4 and described hereinafter. In machine I6,residual solids are separatedfrom liquids by centrifugal force.Conveniently the zone. of discharge of solids thus separated'is adjacentto the inside periphery of the rotor. Liquids may be separatelydischarged fromother zones of the rotor.

Additional water may be added to the material fed to centrifugal machineI6 if desired, such as illustrated at I1, or to the material fed tocentrifugal machine I2, or both, if desired, and/or to the cooker I0, asillustrated, or otherwise, to increase the flow characteristics of thematerial fed to the machine, to reduce the oil content of the meal, toincrease the recovery of oil, and/or otherwise.

For highly preferred operation of the process, to recover meal ofrelatively low oil content and oil in relatively high yield, theover-all material fed to centrifugal machine I2 should contain not morethan approximately 18% by weight of solids, and preferably not more thanapproximately 15% by weight of solids. Since sh usually analyzeapproximately 20% solids and approximately fluids (total oil and water),and rarely vary in solids content beyond the range of approximately from18% to 22% solids, the addition of at least a certain minimum amount ofwater when necessary to reduce the percentage of solids present asindicated is highly desirable. Obviously, water may be added in excessof the amounts indicated, if desired, without harmful effect.

In fact it is preferred that water be added to the fish irrespective oftheir original composition, prior to the entry of the disintegratedcooked sh into the centrifugal machine I2, in an amount, based upontotal solids in the original sh, of at least approximately 50% byweight, and preferably of at least approximately 100% by weight, suchas, of at least approximately 150% by weight. This may take place in thecooker, in a disintegrator, in a slurry tank, at the pump and/or at anyother suitable point. and/ or manner.

For example, at least 10 lbs. of water is preferably added per 100 lbs.of total original fish, and preferably at least 20 lbs., such as atleast 30 lbs., the original fish being calculated as 20% solids. Sincesh are largely of this average solids content, and vary not widelytherefrom, this formula for the addition of water may be followed, inview of its convenience, irrespective of the original composition of thesh.

Furthermore, for the recovery of meal of relatively low oil content andoil in relatively high yield, it is highly preferred that thetemperature of the disintegrated cooked fish fed to the centrifugalmachine I2 be at least approximately F. and more particularly at leastapproximately F., such as at least approximately F., and that suchtemperature should not exceed approximately F., and more particularlyapproximately 160 F., such as approximately 150 F.

Since the fish in the cooker I0 usually are brought to a considerablyhigher temperature during cooking, care is preferably taken to reducethe temperature to within one or more of the preferred ranges statedabove, prior to the entry of the disintegrated cooked fish into thecentrifugal machine I2.

It is also highly preferred that the eiuent from centrifugal machine I2be brought to a higher temperature, such as in a manner hereinafter tobe more particularly described, prior to its entry into the centrifugalmachine I6, such temperature being preferably at least approximately F.,and more particularly at least approximately F., such as betweenapproximately 200 F. and 210 F. The maximum temperature is, of course,the boiling point of the vWater present, which, at ordinary atmospheric-stroy the vitamin content of vbe objectionable when thefoilis to beused'v-for A S tures' around 215 F. or above, may tend to `4`clethe'poil; which may food or medicinal purposes. When the oil is'to bevusedin paints, this may-not be objectionable. The reheating of theeiiiuent'from centrifugal machine I2, as above indicated, greatlyassists in the efiicient separation of f the oil from this effluent inthe centrifugal machine IS.

' 7 Moreover, it is highly preferred that the cooked fish fed to thecentrifugal machine I2 be inthe 'form of a purnpable'ory flowable slurryand that the disintegration of the cooked fish be suchthat vat least g5by weight, therecL-willpass through v a screen having square op'eningsofapproximately '.625 by .625 inch, and more particularly, of .'52

by inch, and still more particularly a screen of 2?/2 mesh yor a screenof `3 mesh. It is 'also lhighly preferred that the cooked fish shall notbe disintegrated to such an extent that` more than 5%, by Weight, Willpass through a screen of 250 mesh, and more particularly/'ofY 20D-mesh,upon gentle vibration of the screen, it being understoodthat if pressureis applied to the disintegrated fish while on the screen, larger amountsmay pass through due to further disintegration caused by the applicationofpressure.

A considerable amount of disintegration takes place in the cooker,particularly when the cooker is of the continuous type, anddisintegrationfwill also be effected by they pump II, particularly whenthis pump is of a type adapted toeifect disintegration, 'such as of lthegear' typegj-Also due tothe disintegration and the flow Iof therdisintegrated fish in the presence of water,` a

v flowable or pumpable slurry is formed. However, Iand as hereinaftermore particularly illustrated and described, a disintegratcrand/or'jslurryfcrming mechanism `may be inserted between the cooker I0and the centrifugal machine' I2, if

desired, `to assist in the disintegration of the sh and/ or theformationof a slurrythereof.

As illustrated, sh solids are' discharged'from lcentrifugal machine I6v(along withsome water) through conduit I8.

rrhese solidsythe same as the solidsfrom machine I2, may be dried in adrier, not shown, and then Iused as fertilizer, or as feed for poultryor otherwise.` As illustrated,

'wateris discharged from centrifugalmachine Iii -through conduit I9.This water may be used as a source of supply of protein and/nor as asource of heat, for example, `as mentioned above. *a As illustrated, oilis dischargedfrom centrifugal machine I6 through conduit 2i). This oilis substantialiy free from water and solids.

When it is desired to obtain a still greater recovery of oil from fishsolids, or meal with a still higher concentration of protein, ormealwith a still lower oil content, or for other reasons, the embodimentillustrated in Figure 2 may be employed, u

In this embodiment, fish are fed toa cooker It as previously described.After a suitable pe- 'riod of cooking, the cooked nsh are fed such as,

' continuously in the form of a slurry and at a preferred temperature,into ,centrifugal machine I2 for separation of solidsfrom liquids.

`From centrifugal machine 'I2 liquids and unseparated solids are passed,such as continuously and at apreferred temperature, into a centrifugalmachine I6. A desired portion or all of the water discharged fromcentrifugal machine I6 through conduit i9, and a portion or-all of thesolids discharged (with some water) from centrifugal vma chine I6through conduit i8, are passed, such as continuously, into a remi'xingtank 23 where they are-mixedwith a portion or all of the solidsdischarged through conduit I3 from the centrifugal machine I2. u

The water discharged from centrifugal machine IB through conduit I9 ofFigure l or yFigure .2 is known as stick-water, and a part vor allrofthis water (usually a Ipart only) may be recycled to the cooker I0 or toany other point in Figure 1 or Figure 2,y such as, to a lpoint betweenIthe cooker Il) and centrifugal machine I2'; forf.the purposespreviously described. Thus, if apor- -tion is so recycled, theremainder' may go` vtothe reiniging tank 23. to be remixedwiththeteiiluents delivered through conduits I3 and I8. e Y

- The constituentsso remixed are passed, such as continuously and at apreferred temperature as mentioned abovey for the iniiuent tocentrifugal machine I2, through conduit 24 into a k'censtrifugal machine25, of a type similarto the centrifugal machine I2, The liquidandunseparated solids discharged from centrifugal machine25 from thecentrifugal machine 21 `throughv conduits 29` and3, respectively, may betreated, if desired, for recovery of their high protein -content, suchas in a suitable evaporator illustrated at 3|. l Y The solids which aredischarged through conduit 32 from the centrifugal machine 25' may bepassed to a drier (not shown) to remove residual moisture and to preparethese solids as a meal for feed, orf otherwise. These solids have a verylow oil content, and are especially suited to be used as a highgrade'feed. f

Centrifugal machine I2 (machine 25 being of similar construction) is cfawell-known designlsame or different design, construction and/oroperation whether batch-wise, semi-continuous, continuous or otherwise.Thusl my invention pertains 'to a process, and not to any-particularmachine Aor machines useful in accomplishing my purpose. I I Y As shown,rotor 42 of centrifugal machine I2 is conical in shape, and encloses animpeller member 44, which, as shown, comprises a continuous screw 45attached along its inner helical edge to a cylinder 46, with its outeredge of spiral shape so as to conform yto the shape of the inner conicalsurface or wall 5I of the rotor 42, with which'inner conical surface itcoacts in the impelling of certain solids in a manner to be hereinaftermore particularly described. In a centrifugal machine of this type apulley 41, or other suitable connection to a source of power, isconnected either to the rotor 42 or to the impeller 44, and both membersare caused to rotate, but

at a slightly different speed, such as at a difference of from 10 to 60revolutions per minute, by virtue of being interconnected through adifferential gearbox 48 of well-known design, construction andoperation, or through any other suitable coupling, or device.

Material, fed into the rotor 42 through the conduit 4|, reaches achamber 49 inside the cylinder 46; it then passes into a zone ofcentrifugation 50 between cylinder 46 and the inner wall I of the rotor42 through a series of openings 52 in the cylinder 46. Due tocentrifugal force. generated by the rapid rotation of rotor 42 and itsassociated impeller member 44. and the relative rotational movement ofscrew 45 with respect to inner wall 5|, certain of the fish solids aremoved longitudinally and radially inwardly out of the liquid and thenseparated from contained and/or adhering water and oil while spread outin a thin layer. During this separation certain other solids, such asextremely finely divided fish meal remain in and are carried along withthe Water and oil.

Screw 45 may be either right-hand or lefthand in shape, that is, it mayadvance along cylinder 46 either clockwise or counter-clockwise, and itmay, through its coupling to rotor 42, rotate either faster or slowerthan rotor 42. Furthermore, screw 45 and rotor 42 may rotate together ineither direction, that is, either clockwise or counter-clockwise as seenfrom the gearbox 48. However, the shape of screw 45 and its relativerotation with respect to rotor 42 (by virtue of the characteristics ofthe coupling employed between screw 45 and rotor 42) are co-ordinatedsuch as to tend to impel the material in the zone of centrifugation 50to the left as seen in Figure 3 of the drawings, that 4is toward thedischarge port 56.

In view of the conical shape of the inner wall 5I of rotor 42, on theother hand, the centrifugal force generated in the zone ofcentrifugation 50 increases toward the right as seen in Figure 3,tending to cause the material in said zone to flow to the right, that istoward the discharge l port 54.

The liquor in the zone of centrifugation 50 builds up on wall 5| in amanner such as to have a more or less cylindrical shaped inner surface,the radial distance of which from the. axis of rotation is determinedfor the most part by the position of the discharge port 54, of whichthere may be any desired number spaced circumferentially. In the usualcommercial embodiments of machines of this type these discharge portsare made radially adjustable to increase or decrease their distance fromthe axis of rotation. Due to the highly fluid character of the-water andoil and the associated finely divided fish solids, the liquid and nelydivided solidsin admixture escape along the screw 45 to the right, asseen in Figure 3, to be discharge `from the port 54, instead of beingmoved to the left by the movement of the screw 45 relative tothe surface5|. On the other hand, the bulk of-V the fish solids are thrownoutwardly against the inner wall 5I of rotor 42, where, due to themovement of screw 45 relative to wall 5|, they are irnpelled to the leftas seen in Figure v3 anddischarged at port 56. It will be noted that thearated from the liquids latter materials travel inwardly radially intheir movement to discharge port 56, and as their radial distance fromthe axis of rotation decreases, they eventually are separated fromwater, oil and finely divided solids. Throughout the remaining distanceof their travel to discharge port 56, they are subjected to acentrifugal separating or wringing action whereby residual water and oiltend to separate from the solids being impelled, and flow back to theright as seen in Figure 3.

Thus liquids and unseparated solids flow toward a zone 53 at the largeend of the rotor 42 and are discharged through liquid discharge f ports54, of which there may be any desired number spaced circumferentially.Solids separated from the liquids by centrifugation are impelledlongitudinally of the rotor 42 by the impeller 44 to a zone 55 of therotor which is closer to the axis of rotation than the level of theliquid in the rotor. Separated solids are discharged from the rotorthrough ports 56 in the rotor wall, of which there may be any desirednumber spaced circumferentially, and collected in a section 51 of rotorhousing 58. Solids may be discharged from the machine through a. hopper59 at the bottom of the section 51 of the housing. The mixture ofliquids and unseparated solids, discharged from the rotor through theports 54, is collected in a section 60 of the rotor housing 58 anddischarged from a hopper 6| located underneath this section 60.

Centrifugal machine I6 (centrifugal machine 21 being similar) is ofwell-known design and construction and is more particularly illustratedin Figure 4. However, it is to be understood that centrifugal machineI6, or is equivalent, as described and/or illustrated in the drawings,may be of any other suitable design and/or construction capable ofsimilarly processing the material fed thereto, many of which naturallywill occur to persons skilled in the art, and to designers and others inthe general field to which these and similarly functioning centrifugalmachines pertain. A part or all of this processing may take place in oneor more than one machine, as desired, and of the same or differentdesign, construction and/or operation whether batchwise,semi-continuous, continuous, or otherwise. Thus .my invention pertainsto a process, and not to any particular machine or machines useful inaccomplishing my purpose.

Referring now to Figure 4, the centrifugal ,machine I6 isillustratedwith an inlet connection 1D through which the mixture of liquids andsolids, for example, from conduit I4, may be fed into a feed section 1Iof a bowl 12, with or without added water, for example, from conduit I1.The bowl 12 may be driven from a suitable source of power such as anelectric motor illustrated at 13. The mixture of liquids and solidspasses downwardly through the feed section 1| and outwardly into thezone of separation of the bowl 12. Solids which are sepby centrifugationcollect in a peripheral zone 15 of the bowl 12, and, as illustrated, aredischarged therefrom through port 16, of which there may be any desirednumber spaced circumferentially, in wall 11 of the bowl 12. The ports 16may be equipped with valve closure members, as illustrated at 1l; orports 16 may remain open at all times. In the latter case ports 16conveniently would take the form of nozzles positioned tangential to thepelriphery of the bowl with the port openings facing backwards withrespect to the direction of rotation, and of a size so as to permitsolids to be discharged without the discharge of an inordinate amount ofliquid.v The size of the ports might be made adjustable for thispurpose.

A valve motor is illustrated at 19 for operating valve closure member10, such as, by way of opening port 16 intermittently and automaticallyas the level of solids rises to a predetermined height from the Wall ofthe bowl, so as to discharge solids from the bowl 12 as and whendesired.

A housing 80 collects solids thus discharged from the bowl 12, anddischarges them from the machine through an opening or chute 8|.

Liquids pass upwardly through the separating zone of the bowl 12 whileunder centrifugal force to a dividing cone or disc 83.

The heavier liquid passes around the outer end of cone 03, and movesupwardly to a discharge Zone 84. The heavier liquid, such as water `withdissolved protein, is then discharged from the zone into4 a collector 85which directs the liquid out through the conduit 8E.

The lighter liquid, such as sh oil, passes up the inner side of the cone83 and to a zone 81 of discharge. Liquid is discharged from the zone k81into collector 8B, and passes from the machine through a conduit 09.

W'hile the centrifugal machines particularly described above may be usedconveniently in the process of the invention, it is to be understoodthat other centrifugal machines which perform the same or similarfunctions may be employed without departing from the spirit of theinvention.

Furthermore, while the re-treatment steps of vFigure 2 may be carriedout in separate centrifuges as described, it is to be understood that itis, of course, possible to provide storage tanks which will permitholding solids from the first centrifugal machine, and solids and waterfrom the second centrifugal machine,-until they can be re-treated in thefirst and second centrifugal machines at a time when fish are not beinginitially processed through these two machines, thus eliminating theduplication of machines.

Centrifugal machines of the general type suitable for the separationsaccomplished by centrifugal machines I6 and 21 of Figures l and 2 (andcentrifugal machine |38 of Figure 5b) are disclosed in U. S. Patent2,286,354, and in Chemical and Metallurgical Engineering, July 1943,page 12,1.

A flow diagram .of an embodiment of my invention in somewhat greaterdetail is shown in Figures a and 5b. Referring now more particularly toFigure 5a at |0| is diagrammatically illustrated a cooker for receivingandcooking raw fish and/or parts thereof. Cooker |0| may be of anysuitable design and construction and for this reason it is notillustrated in detail. Preferably, however, cooker |0| is of thecontinuous type since the process as a whole has distinct advantagesfrom the standpoint of continuous operation. It is to be particularlynoted that my process is not onlyexcellently adapted to continuous.operation but also to such operation in a completely enclosed system.

The sh after cooking are delivered through a conduit or chutediagrammatically illustrated at |02 to inlet |03 of a disintegrator |04for the comminuting or disintegrating of the cooked fish. Disintegrator|04 may be of any design and construction suitable for the intendedpurpose. I find that a disintegrator operating on the cenl0 trifugalprinciple to be highly satisfactory, although any other type ofdisintegration or mill, or other device, may be employed for thecomminution of the cooked fish. Preferably the sh are disintegrated toan extent so that a pumpable slurry of the same may be formed in the'slurry tank |05 to which the disintegrated mass is delivered fromdisintegrator |04 through discharge conduit |06. A prime mover fordisintegrator |04 is illustrated diagrammatically at |01 andconveniently may be an electric motor. y

To maintain the disintegrated fish in the form of a slurry in slurrytank |05, an agitator |08 is provided having one or more agitatingblades |00 which are conveniently driven by an electric motorillustrated diagrammatically at ||0.

Water is usually added to theslurry tank |05 in quantity sufiicient toproduce a readily pumpable slurry. In order to produce a meal ofrelatively high protein content, I prefer to employ for slurry makingpurposes, a part of the Water containing protein in solution andrecoveredat a `later stage in the process. This water vbecause of itscontained protein and suspended meal is referred to hereinafter forconvenience by the more or Aless conventional term stick-water Asillustrated, stick-water enters slurry tank |05 through conduit I, theow being controlled by a valve illustrated diagrammatically at I2, whichmay be manually or automatically operated, as desired.

Slurry tank |05, as shown, is connectedito conduit |'|5 which connectsto the inlet of pump ||6 which maybe of any suitable type. Thus `pump|16 maybe a gear pump which, .as illustrated, is provided .with apressure relief valve H1, which may open automatically to return Va partof the slurry from the outlet to theinlet of the pump in the event thatthe pressure at the outlet should build up to a level higher thandesired. The construction and operation of `relief valves of thischaracter are well known in the art and therefore will not be describedin detail.

At I8 and ||9 are illustrated alternate strainers for the straining fromthe slurry of any possible large pieces of fish which might havesurvived the disintegrator |04 and the slurry tank |05. Strainers H8 andH9 may be of conventional design and construction and operation for thepurposes intended. For example, they may be provided with vopen meshlter screens of which the individual openings may have any desireddimensions, such, as approximately from 1/2" x 1/2 to 3A" x 3A". Mesheshaving dimensions approximately of x 5A, (624 x .624" for example) arefound to be very suitable. While one of the strainers i8 or I |9 is inoperation, the other may be opened for cleaning, and since the operationof the valves illustrated to effect this purpose will become at onceapparent to the person skilled in the art, such operation for purposesof brevity will not be described in detail.

The slurry, after being pumped through one of the strainers H8 or H9,passes through conduit E20 to centrifugal machine |2|, whose function issimilar to that of centrifugal machines l2 and 25 of Figures 1 and 2,and which lmay be of the general type of the centrifugal machineillustrated in detail in Figure 3. As previouslypointed out, in thecommercial adaptations of centrifugal machines of this type, the liquiddischarge ports 50 are radially adjustable. In other words, the radialdistance of the discharge ports 54 from the axis of rotation is madeadjustable.

Since, when the centrifugal machine is in operation, the width of theinner wall of the liquid in the direction of (that is parallel to) theaxis of rotation is determined by the radial position of the liquiddischarge ports 54, it follows that this width may be increased bydecreasing the radial distance of the discharge ports 54, and viceversa. For convenience in description, this liquid layer will bereferred to as the pond, and the portion of the rotor 42 to the left, asseen in Figure 3, and not covered by the pond, will be referred to asthe beach. Thus, as seen in Figure 3, the division between the pond andthe beach is more or less generally illustrated by the dotted line |22,it being understood that the space radially outward from the dotted line|22 is occupied by the pond.

It. is preferred to adjust the liquid discharge ports of centrifugalmachine |2| so as to maintain a relatively wide beach as compared to thewidth of the pond, so as to accentuate in centrifugal machine I2| theseparation of solids relatively free from liquids, this beingaccomplished by not only lengthening the relative time of the so-calledwringing action on the solids, but also by starting the wringing actionat a point along the inner wall 5|, of conical rotor 42, at whichrelatively greater centrifugal forces are generated. Thus, it ispreferred to have the width of the pond (measured parallel to the axisof rotation) less than 1/2 of the distance, as projected on to the axisof rotation, from the liquid discharge port 54 to the solids dischargeport 56.

Solids are discharged from centrifugal machine |2| into conduit |23which, as illustrated, in turn discharges into a screw conveyor,diagrammatically illustrated at |24.

Liquids, that is water and oil, containing very finely divided fishsolids, are discharged from centrifugal machine |2| through conduit |25into funnel |26 which may be closed, if desired, and from which theliquids are pumped by pump |21 (which may be similar to pump ||B withappurtenances) to and into centrifugal machine |28 which in constructionmay be in all respects similar to centrifugal machine |2|. Theadjustment of centrifugal machine |28, as contrasted to adjustment ofcentrifugal machine |2|, is

preferably such as to accentuate the separation of liquids from solids,that is liquids relative ly free from solids, and accordingly the liquiddischarge ports 54 are adjustably positioned closer to the axis ofrotation, so as to maintain a somewhat wider pond than is maintained incentrifugal machine |2|. 'I'hus the width of this pond may be greaterthan 1/ of the distance,l

as projected on to the axis of rotation, from liquid discharge port 54to solids discharge port 56. Preferably, in centrifugal machine 2| thebeach is relatively Wide and the pond relatively narrow, whereas incentrifugal machine |28 the beach is relatively narrow and the pondrelatively wide.

Solids are discharged from centrifugal machine |28 through conduit |29into the conveyor |24. In view of the preferred adjustment ofcentrifugal machine |28 as compared to centrifugal machine |2|, thesesolids will contain a somewhat higher (though still relatively low)percentage of residual oil than the solids discharged through conduit|23 from centrifugal machine |2|. However, the percentage of solids fromcentrifugal machine |28 is relatively low as compared to the solids fromcentrifugal machine l2 |2|, so that the oil increase in the overall mealis relatively small.

Liquids are discharged from centrifugal ma.- chine 28 through conduit|30 into funnel |3| which, like funnel |26, may be closed, if desired,though, in the case of either funnel, this need not be resorted to andis more or less a matter of choice. The liquids are pumped from funnel|3| by pump |33 into feed tank |34, it being understood that theseliquids still contain some extremely finely divided fish solids.

Pump |33 may be of any suitable design and construction, and asillustrated, is of the centrifugal type.

The mixture of water, fish oil and extremely finely divided solids ispreferably reheated in feed tank |34. Heat may be supplied by anysuitable means such as through a steam coil disposed Within the tank, asteam jacket about the tank, or otherwise. A connection for supplyingsteam is illustrated at |35.

The reheated mixture from tank |34 is delivered through conduit |36,controlled by valve |37, to the inlet of centrifugal machine |38, of adesign, construction and operation, which may be in all respects similarto centrifugal machines I6 and 2l of Figures 1 and 2, and illustrated indetail in Figure 4, with or without the suggested modications withrespect to the discharge nozzles, etc.

Fish oil separated in centrifugal machine |38 is discharged therefromthrough conduit |40, which may lead to a storage tank, or to any otherdesired point such as for polishing or refining, not shown.

Water separated in centrifugal machine |38 is discharged through conduit|4|, and separated fish meal (with some Water) through conduit |42. Asillustrated, conduits |4| and |42 connect with conduit |43 which leadsto stick-water tank |44.

As pointed out previously, a part of the stickwater is preferablyrecycled through conduit to slurry tank |05 (or to cooker IDI), orotherwise. For this purpose, pump |45 having an inlet connection |4t`positioned inside of tank |44 and an outlet connection |41 joined toconduit is provided. Pump |45 may be of any suitable type, and asillustrated, is a centrifugal pump.

That portion of the stick-water that is not recycled, fiows from tank|44 through outlet |48, which, if desired, may lead to an evaporator,not shown, for evaporation of water and the recovery of concentratedprotein liquor, or it may be otherwise disposed of, such as discarded.

It will, of course, be understood that the meal delivered throughconduits |23 and |29 to conveyor |24, may be delivered by the conveyor|24 to a drier, not shown, for the production of dry meal ready forpackaging, such as in bags.

It is, of course, understood that any type of fish may be treated by myprocess. Typical types of fish which are currently processed in largevolume for the recovery of fish oil and fish meal are sardine, pilchard,herring, salmon, menhaden, rose fish, etc. Fish reduction operations arefrequently carried on in conjunction with canning operations, the wastefrom the canning plant. Called offal, being sent to the fish reductionplant for the recovery of fish oil and meal therefrom. Whole fish mayalso be reduced in such plants. Fish livers may also be reduced in thismanner.

The advantages of my process over prior art processes, include arelatively high recovery of available fish oil (such as up to 97%, andmore of the oil content of the fish material processed).

as well as a relatively high recovery of available iish meal (such as upto 99% and more of the meal content of the fish material processed).Furthermore, my process may be operated continuously in a closed andbalanced system, requiring a minimum of operating personnel, which i's adecided economicr advantage. Moreover, meal produced by my process has arelatively high protein content, and a relatively low oil content, ascompared to meal produced by the usual prior art processes, and without.the use of solvent extraction. There is no danger of the presence ofresidual solvent in the meal produced by my process, and consequently,meal produced by my process has greater appeal from the standpoint ofhog, cattle and-poultry feed.

Then too, regardless of the type, age or other characteristics of thefish being handled, my process requires a minimum of adjustment,`if any,to'adapt it to the particular sh (which term includes o'ifal and liversthereof) being handled. A screw press on the other hand, yrequires con-ystantv adjustment to adapt it to the type, age or other characteristicsof the sh being handled.

Also in the case of a screw press (but not in my process) the cookerrequires constant adjustment to maintain a cooked fish of a consistencythat will allow proper pressing in the screw press.

It is, of course, well understood in the art, that the oil content offish varies not only with the species of fish, b ut also with theseasons of the year and other factors. Consequently, the followingexample of the operation of my process is to be regarded as merelyillustrative, and is subject to wide variation, depending not only uponvariations in fish, but also in the results which may be desired, aswell as other factors,

By way of illustration, it is assumed that the plant is designed tohandle five tons of fish (which term includes offal and livers) perhour, and that the average analysis of the fish is 55% water, 20% mealand 25% oil. Accordingly, the feed to cooker l! will be at the rate of10,000 pounds/'of fish per hour. It is assumed that the fish are cookedby direct steam, and that due tov the condensation of steam, 3500 poundsof water per hour are added to the fish in the cooker |0|, so that thefeed to disintegrator A| 04 and into slurry tank |05 is at the rate of13,500 pounds per hour. In this illustrative example, stick-waterisadded to slurry tank |05 through conduit at the rate of 3000 poundsper hour, making the rate of discharge from slurry tank |05 throughconduitA |15, pump H5, one of the strainers i0 vand ||9 and conduit |20into centrifugal machine |2|, 16,500 pounds per hour; this feedanalyzing 12,000 pounds of water, 2500 pounds of oil, land 2000 poundsof meal.

In this illustrative example, the solids discharged from centrifugalmachine |2| through conduit |23 and into conveyor |24, analyze on anhourly basis as follows: 1669 pounds. of mealon a dry basis, 1702 poundsof moisture in the meal, and 33 pounds of cil in the meal, or 2% basedondry meal.

Accordingly, liquor is delivered from centrifugal machine 52| throughconduit |25, funnel |20, pump |21 te and into centrifugal machine |28 atthe rate of 13,096 pounds per hour; this lfeed analyzing 10,298 poundsof water, 2467y pounds of oil and 331 pounds of meal. v

Since centrifugal machine |28 is being operated as a liquid clarifier,as distinguished from centrifugal machine |2|, which is being operatedasa solids press, the solids discharged from centrifugal machine |28through conduit |29-and into conveyor |24, will run somewhat higher inliquid content,` and inV this illustrative example, the analysis, on anhourly basis, is as follows: Meal 806 pounds, moisture in meal 460pounds, and oil inI meal 9 pounds or 3% ofthe meal on a dry basis. Itwill bev noted that while this meal has a somewhat higher oil content,the amount of: meal'is relatively small compared to the meal deliveredthrough conduit |23. I f As a resultof the separation of these solids,the flow of liquor from centrifugal machine |28 through conduit |30,funnel |3| and pump l|33 to reheat feedtank |34, will be at the rate of12,321 pounds per hour, this lliquor analyzing on an hourly basis, 9838pounds of water, 2456 pounds of oil, and pounds of meal. This liquor,after reheating say to a temperature vof' about 200 to 2102K, is fedthrough conduit |30 into centrifugal machine |38, at the ratev at whichit enters tank |34. f.

Oil 'is discharged from centrifugal machine |38 through conduit |40 atthe rate of 2422 pounds per hour. Since the rate of feed of oil in thefish in thisillustrative example is 2500 pounds per hour, thisrepresents Aa recovery of oil of 97%.

Bythe use of my process a highly valuable sh oil may be produced. The`residualA water content may be readily brought to below 2% by Weightand lower such as below 1% by weight.

Residual meal, for practicable purposes, may be susbtantially completelyremoved, having in mind the tolerances permitted in the art for asaleable product. The oil may be used as such, or it may f be subjectedto polishing operations for further refinement for which it is ideallysuited.`

From the above figures it will be seen that meal is fed to centrifugalmachine |38 at'the rate of 25 pounds per hour. This meal (withsomeacccmpanying water) is separated in`- centrifugal machine |30, anddischarged through conduits |42 and |43 into stick-water tank |44 alongwith the water discharged from centrifugal. machine |38 through conduit|4|. Of this 25 poundsper hour of meal, 6 pounds per hour is recycled,along with stick-water, back to slurrytank |05. Thus, meal is withdrawnfrom tank |44 through outlet |48, along with stick-water, at the rate of19 pounds per hour. Assuming that thelatter stickwater is not evaporatedto recover its meal `and protein content, the total loss of meal fromthe system is at the rate of 19 pounds per hour, mak.- ing the totalmeal recovered at conveyor |24, 1981 pounds per hour. Since the feed ofmeal in the'sh is at the `rate of 2000 pounds per hour, this representsareoovery of meal of 99%.

It will be understood by those skilled in the art, that in View of allof the possible Variables, not only in the composition of the fish, butalso in the adjustment an'dvoperation of the various pieces of equipmentinvolved, as well as otherwise, the operation, as illustrated by theexample, will rarely be exactly reproduced. Furthermore, depending uponrequirements, the operator may not wish to operate the process toexactly reproduce the results ofthe illustrative example. It is,therefore, to be understood that changes, omissions,additionssubstitutions and/0r modifications might be made withoutdeparting from the spirit of the invention. Y f

As pointed out above, an outstanding advantage of this invention is thatthe use of a screw press fo'r'initially pressing the fish is dispensedwith. However, if desired for any reason, a screw press might-beemployedin conjunction with my invention. Thus, a screw press could be insertedbetween the cooker I and the centrifugal machine |2 of Figure l, whileretaining certain of the advantages of my invention, since the liquorderived from a screw press during fish reduction operations invariablycontains a very substantial quantity of fish solids. These fish solidsmay be more advantageously recovered from the screw press liquor by theemployment of my invention than by prior art methods. Thus, such screwpress liquor might be fed first into centrifugal machine I2 of Figure 1for the initial separation of solids, and then into centrifugal machineI6 of Figure 1 for the separation of remaining solids, and, if desired,the solids and water effluents from centrifugal machine I6 combined withthe solids effluent from centrifugal machine I2 might be processed inthe manner illustrated in Figure 2. Then too, the liquor from a screwpress might be treated as illustrated in Figure 5, although it will beseen from the nature of the recoveries of oil and meal, that the use ofa screw press is non-essential.

By recycling the stick-water through conduit I in Figure 5, for use inthe slurry tank |05 instead of fresh water, for the production of afiowable slurry, the protein and meal (and any residual oil) in thestick-water are recycled through the system. 'I'his results not only inthe recovery of more meal, (and oil), but also of meal with asubstantially higher protein content. A1- though the recycled meal isextremely finely divided, and has passed through the centrifugal machine|28, in view of its intermixture with the fresh feed, a very substantialpart of this meal deposits upon and is recovered with the meal of thefreshly fed cooked fish.

Any desired and suitable temperature or temperatures may be employed inthe various parts and steps of my process, and the same applies topressure or pressures. In the embodiment of the invention illustrated inFigures 5a and 5b, I prefer to have the' mixture in slurry tank |05 at atemperature such that the temperature of the influent into centrifugalmachine I2| will be within at least the broadest range given above forthe feed to centrifugal machine I2. I also prefer that the influent intocentrifugal machine |28 shall be at a temperature at least within suchbroadest range. If found necessary, heat insulation may be provided toeffect this purpose, and/or a reheater may be installed betweencentrifugal machines |2| and |28, or other provisions may be made.However, ordinarily and depending somewhat on design, the materials passthrough these two machines at such a rate so that very little loss ofheat is experienced between slurry tank |05 and reheat tank |34.

When stick-water is recycled the application of external heat to slurrytank |05, or otherwise, is usually unnecessary for the stick-water isusually quite warm. However, a steam coil or heating jacket, or othermeans may be provided for supplying heat to slurry tank |05, if desired.

On the other hand, since the disintegrated cooked fish may be stillquite hot upon entering slurry tank |05 from disintegrator |04, andsince the recycled stick-water is usually quite warm, it may becomenecessary or desirable to cool the slurry in slurry tank |05, in whichcase the same provision may be made, or if already made then used, forthe circulation of cold brine, or other cooling medium, through the coiland/or jacket, or other provision for cooling may be made.

As notedabove, when separating fish oil from water such as incentrifuges I6, 21 and/or |38, I usually prefer that the feed liquor berelatively hot, such as, at least F. and more particularly at least F.or 200 F. Also, as noted above, boiling is considered the practicableupper limit which at atmospheric pressure is in the neighborhood of 212F. Should elevated pressure be employed the boiling temperature would.of course, be correspondingly raised. On the other hand, it would becorrespondingly reduced in the case of reduced pressures.

The centrifuging of the bulk of the meal after its separation fromcontact with the liquids such as is accomplished in centrifugal machines|2, 25, |2| and |28 of the drawings, is preferably under conditionsincluding centrifugal force as to reduce the oil content of the mealbased on dry meal to at least 4%, and more preferably to at least 3%,such as to at least 2%. It will be noted in the illustrative examplethat the oil content on a dry basis of the fish solids discharged fromcentrifugal machine I2| through conduit |23 is reduced to at least 2 andthat the oil content on a dry basis of the fish solids discharged fromcentrifugal machine |28 through conduit 29 is reduced to at least 3%. Itis also preferred that this centrifuging and separation of fish solidsfrom liquids be such as to reduce the concentration of fish solids inthe liquid effluents from these machines, that is in this step of theprocess, wherein solids are brought out of contact with liquids andseparately centrifuged, to at least 5%. such as to at least 3%, or 2%,or even to at least 1%, or 0.5%, for it is by the separate centrifugingof thefish solids out of contact with the main body of the liquids thata low oil content in the fish meal is primarily obtained. Since the oilthus separated from the meal is added to the main body of the separatedliquids which comprise the effluent from the first stage of the processand the influent into the second stage of the process, it follows thatoil recoveries are increased with decrease in the oil content of theseparately centrifuged meal and with decrease in the solids content ofthe liquid effluent from the first stage of the process.

It will be noted in the illustrative example that the solids content ofthe liquid effluent flowing from centrifugal machine |2| through conduit|25 is reduced to at least 3% and that the solids content of the liquideflluent flowing from centrifugal machine |28 through conduit |30 isreduced to at least 0.2%.

Moreover, a low solids content in the combined aqueous effluents fromthe second stage of the process, for example, from centrifugal machineIB of Figure 1 or from centrifugal machine 2l of Figure 2 or centrifugalmachine |38 of Figure 5b, is advantageous when these combined aqueouseffluents are to be treated in an evaporator, and particularly in anevaporator of the tubular type, for the production of a concentratedproteincontaining liquid, since the lower such solids content, the lesslikely it is that difficulty will be experienced with clogging of theevaporator.

While reference has been made to the discharge of some water along withthe separated fish solids in the second stage separation steps, that isfrom centrifugal machines I6, 2l and |38 of the drawings, it is to beunderstood that the percentage of water discharged along with thesesolids is not particularly critical as long as effective separation offish oil is effected. In the ordinary operation of centrifugal machinesof this type, the

separated effluent containing the solids ranges from 20 to'30% ofthetotal feed, such as 25%, and the percentage of solids in this effluentin ordinary operation is less than 5 or 6%, such as for example,approximatelyI 1%. -It will be understood that the otheraqueous effluentwhich isdischarged forms a barrier'V during the separation between theseparated fish oil and the aqueous effluent containing the separatedsolids.

However, and as above pointed out, it is to be understood that any othertype of centrifugal machine suitable for effecting this separation maybeemployed, and it is conceivable that when the solids content in theinnuent is reduced to an extremely low value by the previous processing,that a continuous discharge of solids from the bowl might be dispensedwith and that these solids may be permitted to build up on the innerwall of the bowl and periodically removed as is common in certain typesof solids separation.

Centrifugal machines l2, 25, |21 and |28 may, of course, be of anysuitable size, design, construction and mode or theory of operation, andwhile the use of a conical bowl, as illustrated, is convenient, it istov be understood that the boWl may have any otherA shape. and/orinterior design and construction, suitable to effect the intendedpurpose. Thus merely for purposes of illustration, a typical machine ofthe type shown and particularly described has a frusto-conical bowlwhich is approximately 22 inches long in the direction of its axis, is'approximately 14 inches in diameter at its large end and isapproximately 8 inches in diameter at its small end. In this machine thebowl normally vrotates at a speed of- 3250 revolutions per minute.

Likewise, and as pointed out above,r the bowls of centrifugal machinesI6, 21 and- ISB-of the drawings may, of course, be of any suitable size,design, construction and mode or theory of operation, and while aparticular bowl has been illustrated and particularly described, it isto be understood that the bowl may have any other shape and/or interiordesign and construction, suitable to effect the intendedpurpose. Thusmerely for-purposes of illustration, a typical` machine of the typeshown and particularly described has an inside diameter betweendischarge ports of approximately 1'7 inches with the outer diameter ofthe disc stack approximately 11.

inches. The bowl normally is rotated at a speed of approximately 6000revolutions per minute;

The various pumps will, ofcourse, be of capacities and will operate atspeeds calculated to eiect the desired flow of materials, aswill becomeapparent to persons skilled in theart, upon becoming familiar herewith.

The degree to which the fish are cooked for purposes of separation, iswell understood in the art, and as pointed out above, my process permitsa wide latitude in the degree-of cooking. A typical guide at presentgenerally employed in the art for suicient cooking, is to hold a cookedfish by its tail and to consider the fish suitably cooked, if, uponwiggling, all of the meat falls away from the backbone, leaving verylittle or no red coloration as evidence of blood. Cooking may, ofcourse, be effected in any manner whatsoever.

While rny process has been more particularly described in connectionwith the processingA of sh as originally cooked, it is to beAunderstoodr that it can. be applied to the reprocessing of oilcontainingfish meal for the recovery of. oil therefrom, such as the iish mealpress cake from prior 18' art processes in which-'a screwp'ressis'employed; This mealv may: be'mixed-l withwater -which may1rie-ordinary wateror more prefer-ably stick-water and the press cakedisintegrated to-orm a slurry. The percentage of solidsr in the slur-ryliny such case isy preferably limited as herein more particularlydescribedas preferred inthe case of originally cooked fish andsuch-slurry wouldv be otherwise: processed, these-'meas the slurry ofthe originally cooked iish as more particularly described herein.Preference is given to Vtemperature ranges, solids contents ofefliuents'and influents, oil contentsof eflluent solids, etc., all asherein more particularly described. In this manner; the oil content ofrelatively highoil content meal may -be l-eiectively reduced to produceanreajlf of increased 'feedvalue-andlto 'recover addition'siioiifrom-the'ori'ginal meal.

While my invention has been particularlydescribed in connection withthe-problem of separating into itscomponent parts a diiiculty separableintermixture of iish solids, fish oiland Water, it is to be understoodthat my inventionv may be applied to the solution of similar problems inconnection with other materials. v In the case of sh, the difficultiesof separation are greath7 enhanced due to thepresence of an emulsion ofwaterand sh oil, which emulsion is made much more diflicult'to break dueto the presence of sh solids. In the above'particular description, itwill be noted. that prior to my separation of'water and iish oilfromjeach otherby centrifugal force, I reduce the concentration of fishsolids very materially,` leaving only-a small per cent'age offinelydivided shsolids in the' watersh oil emulsionV prior `toY the'separation by cen;- trifugingof. the emulsion into its" componentparts., During this lattercentrifuging step, these residual solids. areseparated, which. also contributes to the easeof breaking the water-fishoil emulsion in the same operation.

It .will be understood that while 'certain arrangements; of apparatus"have been .particularly described in connection with thegures of .thedrawings, fother arrangements involving omissions, additionsV orotherwise, may be. employed without departing from the spirit of theinvention. Furthermore, features .particularly ydiescribed. inconnection with certain iigures of the drawings may "be embodied inother iigures'of thedrawings if desired. For instance, in Figure l or inFigure 2, additional provisionqmaybe madev for the disintegration of thesh and/or the formation of a slurry between the cooker l 0 and thecentrifuge l2, such as that-'illustrated in Figure 5a. Furthermore, itwill be obvious to persons skilledin the artupon becoming familiarwithmy invention that all of the water that it is desired to have presentVin the process may be added at the cooker I0 in Figuresy 1 and' 2;leaving the addition of waterl at l1 entirely optional'. Moreover,temperature may be adjusted by heating, or cooling (if necessary ordesired). at any desired point such as between the cooker I0 and thecentrifuge I2 of Figures 1 andy 2*, bef tween the centriguge l2 yand thecentrifuge I'6 of Figures 1 and 2, at or near the remixing` tank 23 of'Figure 2, and/or between the centrifuge 25 and the centrifuge 21 ofFigure 2.

Thentoo, since the percentage of meal. discharged by the. centrifuge 16of Figures 1 andy?, and particularlyby the centrifuge` 21. of Figure 2and still more particularly by the centrifuge' |38 of Figure 5b isrelativelysmall, the;'separate discharge ofwate'r and meal from thecentrifugesA` 19 is not essential, particularly when the water and mealis to be discarded or not further processed in whole or in part, or whenthe water and meal are to be re-processed together in whole, asillustrated in Figure 2 after re-mixing tank 23, or in part, asillustrated by the recycle of a part of the stick-water in Figures 5aand 5b. Thus While an evaporator for protein recovery is illustrated at3| in Figure 2, it will be understood that this is not essential and maynot even be preferred in many instances, particularly in view of thereduced percentage of meal and the reduced percentage of protein in thewater discharged from the centrifuge 21 due to the reprocessingbeginning at the remixing tank 23.

Likewise one or more strainers such as illustrated at ||8 and I9 inFigure 5a. may be incorporated at any desired point, such'as, betweencooker l and centrifuge |2 of Figure 1 or Figure 2, and while twocentrifugal machines 2| and |28 have been shown in Figure 5b, it will beunderstood that any number of such centrifugal machines may be employedin effecting this step of the process, such as one or more, and inseries, or in parallel, or both, with any desired or suitable radialadjustment of the discharge ports illustrated at 54 in Figure 3. Thesame applies to the step of the process effected by centrifugal machines|6 and |38, or centrifugal machine 21.

For instance, centrifugal machine |2| in Figure b may be duplicated withthe feed through line |20 divided between the two machines, and thecombined vliquid effluents from these two machines may be fed-t0centrifugal machine |28. Such an arrangement has the advantage ofincreased capacity. This is because in Figure 5b the major work ofseparating solids is done by machine 2|. By duplicating this machine assuggested, such solids may be separated at a faster rate. Machine |28 iscapable of handling the reduced solids content present in the combinedeffluents.

Any desired or suitable means may be employed for the application orregulation of heat at any desired point, the means shown and/ ordescribed being largely for purposes of illustration.

Other changes, omissions, additions, substitutions and/or modificationsand apparatus suitable therefor in the practice of my process willbecome apparent to persons skilled in the art upon becoming familiarwith my invention. Therefore it is to be understood that the aboveparticular description is by way of illustration, and that the inventionis not to be limited other than by the scope of the claims.

I claim:

1. A process for removing fish oil from fish solids, comprisingsubjectingA an aqueous slurry of said fish solids to a centrifugal forcesufilcient to separate solids from liquids, subjecting said separatedsolids to a centrifugal force sufiicient to separate residual liquidstherefrom, combining said separated residual liquids with saidfirst-mentioned separated liquids, thereafter subjecting said separatedliquids to a centrifugal force sufficient to separate said liquids intowater and oil phases, and removing said separated oil and water phasesin separate streams from said last centrifuging step.

2. A process for the treatment of cooked fish for the separation of saidcooked fish into meal, oil and water, comprising subjecting said cookedfish to centrifuging under a centrifugal force sufficient to separatesaid cooked fish into two components, one of said componentscomprisingfish solids containing some water and oil and the other ofsaid components comprising water and oil containing some finely dividedfish solids, subjecting said separated fish solids to centrifuging undera centrifugal force sufficient to separate additional oil and watertherefrom, combining said last-mentioned separated water and oil withsaid second-mentioned component comprising water, oil and finely dividedfish solids, thereafter subjecting said second-mentioned component tocentrifuging under a centrifugal force sufiicient to separate saidsecond-mentioned component into at least two phases, one of saidlastmentioned phases comprising fish oil, and separately removing fromsaid last-mentioned centrifuging step said separated fish oil phase.

3. A process for the treatment of cooked fish for the separation of saidfish into fish meal, fish oil and water, comprising forming a slurrythereof with added water under conditions such that said slurry containsat least approximately 10 lbs. of added water per 100 lbs, of originalraw fish, subjecting said slurry at a temperature between approximatelyo F. and 170 F. to centrifuging under a centrifugal force sufficient toseparate said slurry into a solids component coinprising fish solidscontaining some water and oil and a iiuids component comprising waterand oil containing some finely divided fish solids, thereaftercontinuing the application of centrifugal force to said solids componentwhile out of contact with said fluids component to separate additionaloil and water therefrom, returning said additionally separated water andoil to the zone of original separation, separately removing from theforegoing centrifuging step said solids component and said fluidscomponent as finally separated therein, approximately thereaftersubjecting the separated fluids component to centrifuging at atemperature between approximately 180 F. and 215 F. under a centrifugalforce sufficient to separate said fluids component into at least twophases, one of said last-mentioned phases comprising water and fishsolids, and another of said last-mentioned phases comprising fish oil,and separately removing from said lastmentioned centrifuging step saidphases as finally separated therein.

4. The process of claim 3 in which an admixture of the finally separatedfish solids and water is recycled and employed in the formation of theslurry.

5. A process for the treatment of cooked fish for the separation of saidfish into fish solids, fish oil and water, comprising forming a slurrythere- 0f with added water under conditions such that said slurrycontains at least approximately 30 lbs. of added water per lbs. oforiginal raw fish and such that at least 95% of the fish solids willpass through a screen having square openings with dimensions of .625 by.625 but less than 5% will Pass through a screen o f 250 mesh,subjecting said slurry at a temperature between approximately F. and 150F. to centrifuging under a centrifugal force sufficient to separate saidslurry into a solids component comprising fish solids containing somewater and oil and a fluids component comprising water and oil containingsome finely divided fish solids, thereafter continuing the applicationof centrifugal force to said solids component while out of contact withsaid fluid component to separate additional oil and water therefrom,returning said additionally separated water and oil to the zone of saidfirstmentioned separation, separately removing from the foregoingcentrifuging step said solids component and said uids component asfinally separated therein, thereafter subjecting the separated fluidscomponent to centrifuging at a tempera.- ture between approximately 200F. and 210 F. under a centrifugal force sufficient to separate saidfluids component into at least two phases, one of said last-mentionedphases comprising water and fish solids, and another of saidlastmentioned phases comprising fish oil, separately removing from, saidlast-mentioned centrifuging step said phases as finally separatedtherein, and employing an admixture of the fish solids and waterseparated in said last-mentioned centrifuging as a source of added waterin the formation of said slurry.

6. A process for the treatment of cooked sh for the separation of saidfish into fish meal, sh oil and water, comprising forming a slurrythereof with added water under conditions such that said slurry containsat least approximately 30 lbs. of added water per 100 lbs. of originalraw fish, subjecting said slurry at a temperature between approximately130 F. and 160 F. to centrifuging under a centrifugal force sufficientto separate said slurry into a solids component comprising fish solidscontaining some water and oil and a iiuids component comprising waterand oil containing some nely divided fish solids, and thereaftercontinuing the application of centrifugal force to said solids componentwhile out of contact with said uids component to separate additional oiland water therefrom, returning said additionally separated water and oilto the Zone of said first-mentioned separation, separately removing fromthe foregoing centrifuging step said solids component and said fluidscomponent as finally separated therein, thereafter subjecting theseparated fluids component to centrifuging at a temperature betweenapproximately 200 F. and 210 F. under a centrifugal force sufcient toseparate said fluids component into three parts, one of saidlast-mentioned parts comprising protein-containing water, another ofsaid last-mentioned parts comprising an admixture of water and sh solidscontaining residual oil, and another of said last-mentioned partscomprising fish oil, separately removing from said last-mentionedcentrifuging step said phases as finally separated therein, andrecycling an admixture of fish solids and water derived from saidlast-mentioned centrifuging for use as the source of added water in theformation of said slurry, the amount added being based upon the liquidcomponent of said last-mentioned admixture.

7. A process for the treatment of fish oil containing fish meal for theseparation of said fish meal into fish meal of reduced oil content andiish oil, said first-mentioned fish meal containing more than 4% byweight of fish oil, comprising forming a slurry of said sh meal withadded water under conditions such that said slurry contains not morethan approximately 18% by weight of fish solids, subjecting said slurryat a temperature between approximately 90 F. and 170 F. to centrifugingunder a centrifugal force sufficient to separate said slurry into asolids component comprising sh solids containing some water and oil anda fluids component comprising water and oil containing some finelydivided fish solids. thereafter continuing the application ofcentrifugal force to said solids component while out of contact withsaid fluids component to separate additional oil and water therefrom,returning said additionally separated water and oil to the zone of saidfirst-mentioned separation, separately removing from the foregoingcentrifuging step said solids component and said fluids component asfinally separated therein, thereafter subjecting the separated fluidscomponent to centrifuging at a temperature between approximately F. and215 F. under a centrifugal force sufficient to separate said fluidscomponent into at least two phases, one of said lastmentioned phasescomprising water and iish solids, and another of said last-mentionedphases comprising sh oil, and separately removing from saidlast-mentioned centrifuging step said phases as finally separatedtherein.

8. The process of claim 7 in which an admixture of the finally separatedfish solids and water is recycled and employed in the formation of theslurry.

9. A. process for the treatment of cooked fish livers for the separationof said fish livers into fish meal and fish oil, comprising forming aslurry thereof with added water under conditions such that said slurrycontains not more than 18% by weight of fish solids, subjecting saidslurry at a temperature between approximately 90 F. and F. tocentrifuging under a centrifugal force sufcient to separate said slurryinto a solids component comprising sh solids containing some.

water and oil and a fluids component comprising water and oil containingsome finely divided fish solids, thereafter continuing the applicationof centrifugal force to said solids component while out of contact withsaid fluids component to separate additional oil and water therefrom,returning said additionally separated water and oil to the Zone of saidfirst-mentioned separation, separately removing from the foregoingcentrifuging step said solids component and said fluids components asfinally separated therein, thereafter subjecting the separated fluidscomponent to centrifuging at a temperature between approximately F. and215 F. under a centrifugal force sufficient tc separate said iiuidscomponent into at least two phases, one of said last-mentioned phasescomprising water and fish solids, and another of said last-mentionedphases comprising fish oil, and separately removing from saidlastmentioned centrifuging step said phases as finally separatedtherein.

10. The process of claim 9 in which an admixture of the finallyseparated fish solids and water is recycled and employed in theformation of the slurry.

WALTER C. DAVlS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,840,715 Hiller Jan. 12, 19322,286,354 Fitzsimmons June 16, 1942 OTHER REFERENCES Chem. and Met.Eng., July 1943, pages 120-121. Y

1. A PROCESS FOR REMOVING FISH OIL FROM FISH SOLIDS COMPRISINGSUBJECTING AN AQUEOUS SLURRY OF SAID FISH SOLIDS TO A CENTRIFUGAL FORCESUFFICIENT TO SEPARTAE SOLIDS FROM LIQUIDS, SUBJECTING SAID SEPARATEDSOLIDS TO A CENTRIFUGAL FORCE SUFFICIENT TO SEPARATE RESIDUAL LIQUIDSTHEREFROM, COMBINING SAID SEPARATED RESIDUAL LIQUIDS WITH SAIDFIRST-MENTIONED SEPARATED LIQUIDS, THEREAFTER SUBJECTING SAID SEPARATEDLIQUIDS TO A CENTRIFUGAL FORCE SUFFICIENT TO SEPARATE SAID LIQUIDS INTOWATER AND OIL PHASES, AND REMOVING SAID SEPARATED OIL AND WATER PHASESIN SEPARATE STREAMS FROM SAID LAST CENTRIFUGING STEP.